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Michihiko Ike - One of the best experts on this subject based on the ideXlab platform.
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1,4-Dioxane degradation characteristics of Rhodococcus aetherivorans JCM 14343.
Biodegradation, 2018Co-Authors: Daisuke Inoue, Tsubasa Tsunoda, Yamamoto Norifumi, Michihiko Ike, Kazunari SeiAbstract:Rhodococcus aetherivorans JCM 14343 can degrade 1,4-Dioxane as a sole carbon and energy source. This study aimed to characterize this 1,4-Dioxane degradation ability further, and assess the potential use of the strain for 1,4-Dioxane removal in industrial wastewater. Strain JCM 14343 was able to degrade 1,4-Dioxane inducibly, and its 1,4-Dioxane degradation was also induced by tetrahydrofuran and 1,4-butanediol. The demonstration that 1,4-butanediol not only induced but also enhanced 1,4-Dioxane degradation was a novel finding of this study. Although strain JCM 14343 appeared not to be an effective 1,4-Dioxane degrader considering the maximum specific 1,4-Dioxane degradation rate (0.0073 mg-Dioxane/mg-protein/h), half saturation concentration (59.2 mg/L), and cell yield (0.031 mg-protein/mg-1,4-Dioxane), the strain could degrade over 1100 mg/L of 1,4-Dioxane and maintain its degradation activity at a wide range of temperature (5-40 °C) and pH (4-9) conditions. This suggests the usefulness of strain JCM 14343 in 1,4-Dioxane treatment under acidic and cold conditions. In addition, 1,4-Dioxane degradation experiments in the presence of ethylene glycol (EG) or other cyclic ethers revealed that 1,4-Dioxane degradation by strain JCM 14343 was inhibited in the presence of other cyclic ethers, but not by EG, suggesting certain applicability of strain JCM 14343 for industrial wastewater treatment.
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1,4-Dioxane degradation potential of members of the genera Pseudonocardia and Rhodococcus.
Biodegradation, 2016Co-Authors: Daisuke Inoue, Tsubasa Tsunoda, Yamamoto Norifumi, Kazunari Sei, Kazuko Sawada, Yuji Saito, Michihiko IkeAbstract:In recent years, several strains capable of degrading 1,4-Dioxane have been isolated from the genera Pseudonocardia and Rhodococcus. This study was conducted to evaluate the 1,4-Dioxane degradation potential of phylogenetically diverse strains in these genera. The abilities to degrade 1,4-Dioxane as a sole carbon and energy source and co-metabolically with tetrahydrofuran (THF) were evaluated for 13 Pseudonocardia and 12 Rhodococcus species. Pseudonocardia dioxanivorans JCM 13855T, which is a 1,4-Dioxane degrading bacterium also known as P. dioxanivorans CB1190, and Rhodococcus aetherivorans JCM 14343T could degrade 1,4-Dioxane as the sole carbon and energy source. In addition to these two strains, ten Pseudonocardia strains could degrade THF, but no Rhodococcus strains could degrade THF. Of the ten Pseudonocardia strains, Pseudonocardia acacia JCM 16707T and Pseudonocardia asaccharolytica JCM 10410T degraded 1,4-Dioxane co-metabolically with THF. These results indicated that 1,4-Dioxane degradation potential, including degradation for growth and by co-metabolism with THF, is possessed by selected strains of Pseudonocardia and Rhodococcus, although THF degradation potential appeared to be widely distributed in Pseudonocardia. Analysis of soluble di-iron monooxygenase (SDIMO) α-subunit genes in THF and/or 1,4-Dioxane degrading strains revealed that not only THF and 1,4-Dioxane monooxygenases but also propane monooxygenase-like SDIMOs can be involved in 1,4-Dioxane degradation.
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biological wastewater treatment of 1 4 Dioxane using polyethylene glycol gel carriers entrapping afipia sp d1
Journal of Bioscience and Bioengineering, 2016Co-Authors: Kazuichi Isaka, Kazunari Sei, Makiko Udagawa, Yuya Kimura, Michihiko IkeAbstract:A biological treatment system for 1,4-Dioxane-containing wastewater was developed using the bacterium Afipia sp. D1, which can utilize 1,4-Dioxane as the sole carbon source. Strain D1 was entrapped in a polyethylene glycol gel carrier to stably maintain it in a bioreactor, and continuous feeding tests were performed to treat model industrial wastewater containing 1,4-Dioxane. 1,4-Dioxane removal activity rapidly increased soon after the start of feeding of influent with 400 mg/L 1,4-Dioxane, and the volumetric removal rate reached 0.67 kg Dioxane/m 3 /d on day 36 by a stepwise increase in loading. The start-up period of the 1,4-Dioxane treatment reactor was approximately 1 month, and stable removal performance was subsequently achieved for more than 1 month. The average 1,4-Dioxane effluent concentration and 1,4-Dioxane removal efficiency were 3.6 mg/L and 99%, respectively, during stable operation. Further 1,4-Dioxane degradation activity of the of the gel carrier was characterized in batch experiments with respect to temperature. The optimum temperature for 1,4-Dioxane treatment was 31.7°C, and significant removal was observed at a temperature as low as 6.9°C. The apparent activation energy for 1,4-Dioxane degradation was estimated to be 47.3 kJ/mol. This is the first report of the development of a 1,4-Dioxane biological treatment system using gel entrapment technology.
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isolation and characterization of bacterial strains that have high ability to degrade 1 4 Dioxane as a sole carbon and energy source
Biodegradation, 2013Co-Authors: Daisuke Inoue, Kazunari Sei, Keiko Miyagaki, Takashi Kakinoki, Kunihiro Fukugasako, Michihiko IkeAbstract:Four novel metabolic 1,4-Dioxane degrading bacteria possessing high ability to degrade 1,4-Dioxane (designated strains D1, D6, D11 and D17) were isolated from soil in the drainage area of a chemical factory. Strains D6, D11 and D17 were allocated to Gram-positive actinomycetes, similar to previously reported metabolic 1,4-Dioxane degrading bacteria, whereas strain D1 was allocated to Gram-negative Afipia sp. The isolated strains could utilize a variety of carbon sources, including cyclic ethers, especially those with carbons at position 2 that were modified with methyl- or carbonyl-groups. The cell yields on 1,4-Dioxane were relatively low (0.179–0.223 mg-protein (mg-1,4-Dioxane)−1), which was likely due to requiring energy for C–O bond fission. The isolated strains showed 2.6–13 times higher specific 1,4-Dioxane degradation rates (0.052–0.263 mg-1,4-Dioxane (mg-protein)−1 h−1) and 2.3–7.8 fold lower half saturation constants (20.6–69.8 mg L−1) than the most effective 1,4-Dioxane degrading bacterium reported to date, Pseudonocardia dioxanivorans CB1190, suggesting high activity and affinity toward 1,4-Dioxane degradation. Strains D1 and D6 possessed inducible 1,4-Dioxane degrading enzymes, whereas strains D11 and D17 possessed constitutive ones. 1,4-Dioxane degradation (100 mg L−1) by Afipia sp. D1 was not affected by the co-existence of up to 3,000 mg L−1 of ethylene glycol. The effects of initial pH, incubation temperature and NaCl concentration on 1,4-Dioxane degradation by the four strains revealed that they could degrade 1,4-Dioxane under a relatively wide range of conditions, suggesting that they have a certain adaptability and applicability for industrial wastewater treatment.
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evaluation of the biodegradation potential of 1 4 Dioxane in river soil and activated sludge samples
Biodegradation, 2010Co-Authors: Kazunari Sei, Daisuke Inoue, Takashi Kakinoki, Satoshi Soda, Masanori Fujita, Michihiko IkeAbstract:To evaluate the biodegradation potential of 1,4-Dioxane in natural environments, a total of 20 environmental samples including river water, activated sludge, soil from the drainage area of a chemical factory and garden soil were subjected to a 1,4-Dioxane degradation test. The five soil samples from the drainage area of the chemical factory were capable of reducing 100 mg l−1 of 1,4-Dioxane to below the detection limit (0.8 mg l−1) within 33 days. In one activated sludge sample, 100 mg l−1 of 1,4-Dioxane decreased by 69% within 14 days via cometabolic degradation in the presence of 100 mg l−1 of tetrahydrofuran (THF). The ability of all samples to degrade 1,4-Dioxane degradation with or without THF increased after repeated enrichment, except for one soil sample from the drainage area of the chemical factory that was no longer able to degrade 1,4-Dioxane after the third cycle of enrichment. However, most of the samples (14/20) were not able to degrade 1,4-Dioxane degradation. Thus, it can be concluded that the potential for 1,4-Dioxane degradation is not ubiquitously distributed in natural environment.
Kazunari Sei - One of the best experts on this subject based on the ideXlab platform.
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1,4-Dioxane degradation characteristics of Rhodococcus aetherivorans JCM 14343.
Biodegradation, 2018Co-Authors: Daisuke Inoue, Tsubasa Tsunoda, Yamamoto Norifumi, Michihiko Ike, Kazunari SeiAbstract:Rhodococcus aetherivorans JCM 14343 can degrade 1,4-Dioxane as a sole carbon and energy source. This study aimed to characterize this 1,4-Dioxane degradation ability further, and assess the potential use of the strain for 1,4-Dioxane removal in industrial wastewater. Strain JCM 14343 was able to degrade 1,4-Dioxane inducibly, and its 1,4-Dioxane degradation was also induced by tetrahydrofuran and 1,4-butanediol. The demonstration that 1,4-butanediol not only induced but also enhanced 1,4-Dioxane degradation was a novel finding of this study. Although strain JCM 14343 appeared not to be an effective 1,4-Dioxane degrader considering the maximum specific 1,4-Dioxane degradation rate (0.0073 mg-Dioxane/mg-protein/h), half saturation concentration (59.2 mg/L), and cell yield (0.031 mg-protein/mg-1,4-Dioxane), the strain could degrade over 1100 mg/L of 1,4-Dioxane and maintain its degradation activity at a wide range of temperature (5-40 °C) and pH (4-9) conditions. This suggests the usefulness of strain JCM 14343 in 1,4-Dioxane treatment under acidic and cold conditions. In addition, 1,4-Dioxane degradation experiments in the presence of ethylene glycol (EG) or other cyclic ethers revealed that 1,4-Dioxane degradation by strain JCM 14343 was inhibited in the presence of other cyclic ethers, but not by EG, suggesting certain applicability of strain JCM 14343 for industrial wastewater treatment.
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1,4-Dioxane degradation potential of members of the genera Pseudonocardia and Rhodococcus.
Biodegradation, 2016Co-Authors: Daisuke Inoue, Tsubasa Tsunoda, Yamamoto Norifumi, Kazunari Sei, Kazuko Sawada, Yuji Saito, Michihiko IkeAbstract:In recent years, several strains capable of degrading 1,4-Dioxane have been isolated from the genera Pseudonocardia and Rhodococcus. This study was conducted to evaluate the 1,4-Dioxane degradation potential of phylogenetically diverse strains in these genera. The abilities to degrade 1,4-Dioxane as a sole carbon and energy source and co-metabolically with tetrahydrofuran (THF) were evaluated for 13 Pseudonocardia and 12 Rhodococcus species. Pseudonocardia dioxanivorans JCM 13855T, which is a 1,4-Dioxane degrading bacterium also known as P. dioxanivorans CB1190, and Rhodococcus aetherivorans JCM 14343T could degrade 1,4-Dioxane as the sole carbon and energy source. In addition to these two strains, ten Pseudonocardia strains could degrade THF, but no Rhodococcus strains could degrade THF. Of the ten Pseudonocardia strains, Pseudonocardia acacia JCM 16707T and Pseudonocardia asaccharolytica JCM 10410T degraded 1,4-Dioxane co-metabolically with THF. These results indicated that 1,4-Dioxane degradation potential, including degradation for growth and by co-metabolism with THF, is possessed by selected strains of Pseudonocardia and Rhodococcus, although THF degradation potential appeared to be widely distributed in Pseudonocardia. Analysis of soluble di-iron monooxygenase (SDIMO) α-subunit genes in THF and/or 1,4-Dioxane degrading strains revealed that not only THF and 1,4-Dioxane monooxygenases but also propane monooxygenase-like SDIMOs can be involved in 1,4-Dioxane degradation.
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biological wastewater treatment of 1 4 Dioxane using polyethylene glycol gel carriers entrapping afipia sp d1
Journal of Bioscience and Bioengineering, 2016Co-Authors: Kazuichi Isaka, Kazunari Sei, Makiko Udagawa, Yuya Kimura, Michihiko IkeAbstract:A biological treatment system for 1,4-Dioxane-containing wastewater was developed using the bacterium Afipia sp. D1, which can utilize 1,4-Dioxane as the sole carbon source. Strain D1 was entrapped in a polyethylene glycol gel carrier to stably maintain it in a bioreactor, and continuous feeding tests were performed to treat model industrial wastewater containing 1,4-Dioxane. 1,4-Dioxane removal activity rapidly increased soon after the start of feeding of influent with 400 mg/L 1,4-Dioxane, and the volumetric removal rate reached 0.67 kg Dioxane/m 3 /d on day 36 by a stepwise increase in loading. The start-up period of the 1,4-Dioxane treatment reactor was approximately 1 month, and stable removal performance was subsequently achieved for more than 1 month. The average 1,4-Dioxane effluent concentration and 1,4-Dioxane removal efficiency were 3.6 mg/L and 99%, respectively, during stable operation. Further 1,4-Dioxane degradation activity of the of the gel carrier was characterized in batch experiments with respect to temperature. The optimum temperature for 1,4-Dioxane treatment was 31.7°C, and significant removal was observed at a temperature as low as 6.9°C. The apparent activation energy for 1,4-Dioxane degradation was estimated to be 47.3 kJ/mol. This is the first report of the development of a 1,4-Dioxane biological treatment system using gel entrapment technology.
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isolation and characterization of bacterial strains that have high ability to degrade 1 4 Dioxane as a sole carbon and energy source
Biodegradation, 2013Co-Authors: Daisuke Inoue, Kazunari Sei, Keiko Miyagaki, Takashi Kakinoki, Kunihiro Fukugasako, Michihiko IkeAbstract:Four novel metabolic 1,4-Dioxane degrading bacteria possessing high ability to degrade 1,4-Dioxane (designated strains D1, D6, D11 and D17) were isolated from soil in the drainage area of a chemical factory. Strains D6, D11 and D17 were allocated to Gram-positive actinomycetes, similar to previously reported metabolic 1,4-Dioxane degrading bacteria, whereas strain D1 was allocated to Gram-negative Afipia sp. The isolated strains could utilize a variety of carbon sources, including cyclic ethers, especially those with carbons at position 2 that were modified with methyl- or carbonyl-groups. The cell yields on 1,4-Dioxane were relatively low (0.179–0.223 mg-protein (mg-1,4-Dioxane)−1), which was likely due to requiring energy for C–O bond fission. The isolated strains showed 2.6–13 times higher specific 1,4-Dioxane degradation rates (0.052–0.263 mg-1,4-Dioxane (mg-protein)−1 h−1) and 2.3–7.8 fold lower half saturation constants (20.6–69.8 mg L−1) than the most effective 1,4-Dioxane degrading bacterium reported to date, Pseudonocardia dioxanivorans CB1190, suggesting high activity and affinity toward 1,4-Dioxane degradation. Strains D1 and D6 possessed inducible 1,4-Dioxane degrading enzymes, whereas strains D11 and D17 possessed constitutive ones. 1,4-Dioxane degradation (100 mg L−1) by Afipia sp. D1 was not affected by the co-existence of up to 3,000 mg L−1 of ethylene glycol. The effects of initial pH, incubation temperature and NaCl concentration on 1,4-Dioxane degradation by the four strains revealed that they could degrade 1,4-Dioxane under a relatively wide range of conditions, suggesting that they have a certain adaptability and applicability for industrial wastewater treatment.
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evaluation of the biodegradation potential of 1 4 Dioxane in river soil and activated sludge samples
Biodegradation, 2010Co-Authors: Kazunari Sei, Daisuke Inoue, Takashi Kakinoki, Satoshi Soda, Masanori Fujita, Michihiko IkeAbstract:To evaluate the biodegradation potential of 1,4-Dioxane in natural environments, a total of 20 environmental samples including river water, activated sludge, soil from the drainage area of a chemical factory and garden soil were subjected to a 1,4-Dioxane degradation test. The five soil samples from the drainage area of the chemical factory were capable of reducing 100 mg l−1 of 1,4-Dioxane to below the detection limit (0.8 mg l−1) within 33 days. In one activated sludge sample, 100 mg l−1 of 1,4-Dioxane decreased by 69% within 14 days via cometabolic degradation in the presence of 100 mg l−1 of tetrahydrofuran (THF). The ability of all samples to degrade 1,4-Dioxane degradation with or without THF increased after repeated enrichment, except for one soil sample from the drainage area of the chemical factory that was no longer able to degrade 1,4-Dioxane after the third cycle of enrichment. However, most of the samples (14/20) were not able to degrade 1,4-Dioxane degradation. Thus, it can be concluded that the potential for 1,4-Dioxane degradation is not ubiquitously distributed in natural environment.
Shaily Mahendra - One of the best experts on this subject based on the ideXlab platform.
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abiotic and bioaugmented granular activated carbon for the treatment of 1 4 Dioxane contaminated water
Environmental Pollution, 2018Co-Authors: Michelle A Myers, Nicholas W Johnson, Erick Zerecero Marin, Peerapong Pornwongthong, Yun Liu, Phillip B Gedalanga, Shaily MahendraAbstract:Abstract 1,4-Dioxane is a probable human carcinogen and an emerging contaminant that has been detected in surface water and groundwater resources. Many conventional water treatment technologies are not effective for the removal of 1,4-Dioxane due to its high water solubility and chemical stability. Biological degradation is a potentially low-cost, energy-efficient approach to treat 1,4-Dioxane-contaminated waters. Two bacterial strains, Pseudonocardia dioxanivorans CB1190 (CB1190) and Mycobacterium austroafricanum JOB5 (JOB5), have been previously demonstrated to break down 1,4-Dioxane through metabolic and co-metabolic pathways, respectively. However, both CB1190 and JOB5 have been primarily studied in laboratory planktonic cultures, while most environmental microbes grow in biofilms on surfaces. Another treatment technology, adsorption, has not historically been considered an effective means of removing 1,4-Dioxane due to the contaminant's low Koc and Kow values. We report that the granular activated carbon (GAC), Norit 1240, is an adsorbent with high affinity for 1,4-Dioxane as well as physical dimensions conducive to attached bacterial growth. In abiotic batch reactor studies, 1,4-Dioxane adsorption was reversible to a large extent. By bioaugmenting GAC with 1,4-Dioxane-degrading microbes, the adsorption reversibility was minimized while achieving greater 1,4-Dioxane removal when compared with abiotic GAC (95–98% reduction of initial 1,4-Dioxane as compared to an 85–89% reduction of initial 1,4-Dioxane, respectively). Bacterial attachment and viability was visualized using fluorescence microscopy and confirmed by amplification of taxonomic genes by quantitative polymerase chain reaction (qPCR) and an ATP assay. Filtered samples of industrial wastewater and contaminated groundwater were also tested in the bioaugmented GAC reactors. Both CB1190 and JOB5 demonstrated 1,4-Dioxane removal greater than that of the abiotic adsorbent controls. This study suggests that bioaugmented adsorbents could be an effective technology for 1,4-Dioxane removal from contaminated water resources.
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Advances in bioremediation of 1,4-Dioxane-contaminated waters.
Journal of environmental management, 2017Co-Authors: Shu Zhang, Phillip B Gedalanga, Shaily MahendraAbstract:1,4-Dioxane is a contaminant of emerging concern that has been found widespread in groundwater, surface water, and drinking water environments. Many states are implementing lower regulatory advisory levels based on the toxicological profile of 1,4-Dioxane and the potential public health risks. However, the unique chemical properties of 1,4-Dioxane, such as high water solubility, low Henry's law constant, and importantly, the co-occurrence with chlorinated solvents and other contaminants, increase the challenges to efficiently cleanup 1,4-Dioxane. This review summarizes currently available chemical and physical 1,4-Dioxane treatment technologies and focuses on recent advances in bioremediation and monitoring tools. We also include laboratory studies and field applications to propose the next steps in 1,4-Dioxane bioremediation research. It is important to provide useful references to change the industrial and regulatory perception of 1,4-Dioxane biodegradability, to understand treatment mechanisms especially in contaminant mixtures, and to direct research for meeting practical needs.
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a multiple lines of evidence framework to evaluate intrinsic biodegradation of 1 4 Dioxane
Remediation Journal, 2016Co-Authors: Phillip B Gedalanga, Andrew S Madison, Yu Miao, Timothy Richards, Jim Hatton, William Diguiseppi, John T Wilson, Shaily MahendraAbstract:Development of a multiple lines of evidence (MLOE) framework to evaluate the intrinsic biodegradation potential of 1,4-Dioxane is vital to implementing management strategies at groundwater sites impacted by 1,4-Dioxane. A comprehensive MLOE approach was formed to provide significant evidence of natural degradation of 1,4-Dioxane comingled with tetrahydrofuran (THF) within a large, diffuse plume. State-of-the art molecular biological analyses and compound-specific isotope analysis (CSIA) were employed to support more traditional approaches for data analysis (concentration trend analyses, spatial distribution, temporal changes, geochemical biodegradation attenuation indicators, plume mass estimates, and fate and transport modeling). The molecular analyses demonstrated that microorganisms capable of both metabolic and cometabolic degradation of 1,4-Dioxane were present throughout the groundwater plume, whereas the CSIA data provided supporting evidence of biodegradation. 1,4-Dioxane biomarkers were present and abundant throughout the 1,4-Dioxane plume, and our biomarkers tracked the plume with reasonable accuracy. Evidence also suggests that THF-driven cometabolic biodegradation as well as catabolic 1,4-Dioxane biodegradation were active at this site. These data supplemented the traditional lines of evidence approaches, which demonstrated that 1,4-Dioxane attenuation was occurring across the groundwater plume and that nondestructive physical processes alone did not account for the observed 1,4-Dioxane attenuation. This MLOE framework combining new and traditional analyses demonstrates that this site has a significant capacity for intrinsic biodegradation of 1,4-Dioxane. ©2016 Wiley Periodicals, Inc.
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a multisite survey to identify the scale of the 1 4 Dioxane problem at contaminated groundwater sites
Environmental Science and Technology Letters, 2014Co-Authors: David T Adamson, Shaily Mahendra, Kenneth L Walker, Sharon R Rauch, Shayak Sengupta, Charles J NewellAbstract:1,4-Dioxane (Dioxane) is an emerging groundwater contaminant that has significant regulatory implications and potential remediation costs, but our current understanding of its occurrence and behavior is limited. This study used intensive data mining to identify and evaluate >2000 sites in California where groundwater has been impacted by chlorinated solvents and/or Dioxane. Dioxane was detected at 194 of these sites, with 95% containing one or more chlorinated solvents. Dioxane frequently co-occurs with 1,1,1-trichloroethene (1,1,1-TCA) (76% of the study sites), but despite this, no Dioxane analyses were conducted at 332 (67%) of the sites where 1,1,1-TCA was detected. At sites where Dioxane has been identified, plumes are dilute but not large (median maximal concentration of 365 μg/L; median plume length of 269 m) and have been delineated to a similar extent as typically co-occurring chlorinated solvents. Furthermore, at sites where Dioxane and chlorinated solvents co-occur, Dioxane plumes are frequently...
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Identification of Biomarker Genes To Predict Biodegradation of 1,4-Dioxane
Applied and environmental microbiology, 2014Co-Authors: Phillip B Gedalanga, Peerapong Pornwongthong, Rebecca Mora, Sheau-yun Dora Chiang, Brett R. Baldwin, Dora Ogles, Shaily MahendraAbstract:Bacterial multicomponent monooxygenase gene targets in Pseudonocardia dioxanivorans CB1190 were evaluated for their use as biomarkers to identify the potential for 1,4-Dioxane biodegradation in pure cultures and environmental samples. Our studies using laboratory pure cultures and industrial activated sludge samples suggest that the presence of genes associated with Dioxane monooxygenase, propane monooxygenase, alcohol dehydrogenase, and aldehyde dehydrogenase are promising indicators of 1,4-Dioxane biotransformation; however, gene abundance was insufficient to predict actual biodegradation. A time course gene expression analysis of Dioxane and propane monooxygenases in Pseudonocardia dioxanivorans CB1190 and mixed communities in wastewater samples revealed important associations with the rates of 1,4-Dioxane removal. In addition, transcripts of alcohol dehydrogenase and aldehyde dehydrogenase genes were upregulated during biodegradation, although only the aldehyde dehydrogenase was significantly correlated with 1,4-Dioxane concentrations. Expression of the propane monooxygenase demonstrated a time-dependent relationship with 1,4-Dioxane biodegradation in P. dioxanivorans CB1190, with increased expression occurring after over 50% of the 1,4-Dioxane had been removed. While the fraction of P. dioxanivorans CB1190-like bacteria among the total bacterial population significantly increased with decrease in 1,4-Dioxane concentrations in wastewater treatment samples undergoing active biodegradation, the abundance and expression of monooxygenase-based biomarkers were better predictors of 1,4-Dioxane degradation than taxonomic 16S rRNA genes. This study illustrates that specific bacterial monooxygenase and dehydrogenase gene targets together can serve as effective biomarkers for 1,4-Dioxane biodegradation in the environment.
Francesc Ventura - One of the best experts on this subject based on the ideXlab platform.
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Dioxanes and dioxolanes in source waters occurrence odor thresholds and behavior through upgraded conventional and advanced processes in a drinking water treatment plant
Water Research, 2019Co-Authors: Guillem Carrera, Lidia Vegue, Alejandra Hernandezvalencia, Francesc Ventura, Roque Devesa, Rosa M BoledaAbstract:Abstract Over the last years, the human probable carcinogen 1,4-Dioxane and alkyl-1,3-Dioxanes and dioxolanes have been detected and identified as the cause of several pollution episodes in the Llobregat River (Catalonia, NE Spain) and its aquifer. It is an issue of major concern to study these compounds which are released to the environment by resin manufacturing plants' spills and wastewater discharges spread along rivers and reach drinking water treatment plants (DWTPs) in order to protect the environment and public health. In this study four seasonal sampling campaigns were carried out over a year to determine the removal efficiency of the Dioxanes and dioxolanes at each step of a DWTP including ozonation, granular activated carbon filters, ultrafiltration and reverse osmosis step's treatments. Additionally, a weekly sampling monitoring of 1,4-Dioxane and alkyl-1,3-Dioxanes and dioxolanes in raw water, groundwater and finished water was performed at a DWTP over more than two years. Aqueous odor concentration thresholds (OTCs) were established by the three-alternative forced choice method (3-AFC). Following a previous published methodology, samples were analyzed and results showed that the advanced treatment (Ultrafiltration followed by reverse osmosis) line removes more efficiently 1,4-Dioxane, alkyl Dioxanes and dioxolanes (80 ± 6% for 1,4-Dioxane, 97 ± 7% for 5,5-DMD and 100 ± 0% for 2,5,5-TMD) than the upgraded conventional treatment line (ozonation followed by granular activated carbon filters) (−12 ± 50%, 25 ± 62% and 50 ± 51% respectively), where some desorption processes were eventually observed. From the monitoring study, results suggest that the presence of 1,4-Dioxane is not only due to spills, but also from other sources of contamination. Whereas dioxolanes almost completely disappeared in time, 1,4-Dioxane's concentrations remained low and fluctuant. A background concentration of 1,4-Dioxane in surface waters (∼1 μg/L) has been determined with a relevant concentration up to 11.6 μg/L of 1,4-Dioxane in groundwater. The perception values for some of the studied compounds were extremely low (few ng/L only), which confirms the relevancy of this group of compounds as malodorous agents in waters.
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simultaneous determination of the potential carcinogen 1 4 Dioxane and malodorous alkyl 1 3 Dioxanes and alkyl 1 3 dioxolanes in environmental waters by solid phase extraction and gas chromatography tandem mass spectrometry
Journal of Chromatography A, 2017Co-Authors: Guillem Carrera, Lidia Vegue, Ma Rosa Boleda, Francesc VenturaAbstract:Abstract 1,4-Dioxane is a synthetic industrial solvent used in various industrial processes, and it is a probable human carcinogen whose presence in the aquatic environment is frequently reported. Alkyl-1,3-Dioxanes and alkyl-1,3-dioxolanes are compounds that have been identified as causing several odor episodes in waters over the last years, with the result of downtime of drinking water treatment plants. According to published studies, some of these episodes may be caused either by resins synthesis processes, or by industrial residues added to dehydrated sludge in wastewater treatment plants (WWTPs) in order to increase biogas production efficiency. Analytical methods based on closed loop stripping analysis (CLSA) are routinely used when taste and odor events appear, but this technique has demonstrated to be unsuitable to determine 1,4-Dioxane at trace levels. In this context, drinking water companies tend to focus on determining odorous compounds, but not on those compounds that are potentially harmful. The suitability of a SPE method and further analysis by GC/MS–MS to simultaneously determine 1,4-Dioxane and alkyl-1,3-Dioxanes and dioxolanes has been demonstrated. Recoveries in surface waters spiked at 25 ng/L ranged from 76% to 105%, whereas method quantification limits (MQLs) varied from 0.7 to 26 ng/L for Dioxanes, and dioxolanes and 50 ng/L for 1,4-Dioxane. Uncertainties were evaluated at two different concentrations, 0.02 μg/L and 0.4 μg/L, with values of 25% for 1,4-Dioxane, and of 16–28% for alkyl-1,3-Dioxanes and alkyl-1,3-dioxolanes for the later. The methodology has been successfully applied to samples from the aquifer of the Llobregat River (NE. Spain).
Xumu Zhang - One of the best experts on this subject based on the ideXlab platform.
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enantioselective access to chiral 2 substituted 2 3 dihydrobenzo 1 4 Dioxane derivatives through rh catalyzed asymmetric hydrogenation
Organic Letters, 2018Co-Authors: Xuguang Yin, Yi Huang, Ziyi Chen, Lin Tao, Qingyang Zhao, Xiuqin Dong, Xumu ZhangAbstract:Rh-catalyzed asymmetric hydrogenation of various benzo[b][1,4]dioxine derivatives was successfully developed to prepare chiral 2-substituted 2,3-dihydrobenzo[1,4]Dioxane derivatives using ZhaoPhos and N-methylation of ZhaoPhos ligands with high yields and excellent enantioselectivities (up to 99% yield, >99% enantiomeric excess (ee), turnover number (TON) = 24 000). Moreover, this asymmetric hydrogenation methodology, as the key step with up to 10 000 TON, was successfully applied to develop highly efficient synthetic routes for the construction of some important biologically active molecules, such as MKC-242, WB4101, BSF-190555, and (R)-doxazosin·HCl.
